This invention relates to a torque wrenche, particularly to a ratchet wrench of variable direction.
Ratchet wrenches with direction-adjusting means are generally complicated in construction. A ratchet wrench which is of simpler construction is shown in FIG. 1. It includes a cylindrical housing with a handle and a plurality of ratchet teeth on the inner side of the wall thereof, a torque transmitting member, which is of a cylindrical body 11 with a circumferential groove of semi-circular cross-section, being mounted in the housing. A pawl member 13 is pivoted to the cylindrical body 11 by means of a pin 14, and can be operated manually through a control knob 12 to change its position relative to the ratchet teeth, so that the cylindrical body can be rotated clockwise or anticlockwise. When a torque is applied, it will be transmitted to the cylindrical body 11 through the housing and the pawl 13. Since the pawl 13 is pivoted, the possible tolerance of the pawl against the torque is limited. If the applied torque is very large, the pawl will break at the portion where it is pivoted. Moreover, the construction of pawl 13 involves complicated machining processes, such as forging, milling, drilling, etc., which do not consistently provide accurate dimensions, thus increasing the tendency for the pawl to be damaged at its pivoted portion.